The work under progress involves the recording of the electrical signals of the retina (electroretinogram--ERG) and the cortex (visually evoked potentials--VEP) as a means of studying the human visual system in the normal and diseased state. The research program includes: (1) the use of a pattern stimulus of constant mean luminance to record the ERG and VEP in patients with retinal cone dysfunction; (2) the investigation of the electrophysiological correlates of amblyopia using the ERG and VEP in adults and the VEP in children; (3) recording of the pattern VEP in normal infants as a means of estimating their visual acuity; (4) the study of retinal and cortical mechanisms of color vision using a bar pattern stimulus and the Stiles increment threshold paradigm.